A method and device for measuring stagnation enthalpy of a high-enthalpy wind tunnel subsonic flow field

Abstract

The application provides a high-enthalpy wind tunnel subsonic flow field test stagnation point enthalpy measurement method and device. The method comprises the following steps: in the high-enthalpy wind tunnel subsonic flow field test, generating a subsonic high-enthalpy flow field through a high-frequency induction plasma generator; collecting stagnation point pressure and flow field static pressure through a measuring probe respectively, and calculating the local Mach number of the flow field and determining the correction factor; obtaining the first stagnation point heat flow and the second stagnation point heat flow of the same flow field position measured through a double heat flow probe; taking the stagnation point enthalpy and the dissociation degree as variables to be solved, and constructing a residual equation group; according to a preset initial value of the variable to be solved, adopting a Newton-Raphson numerical iteration algorithm, calculating a partial derivative matrix and solving a linear equation to determine the correction amount of the variable to be solved, gradually correcting the variable to be solved, and according to the current step of the dissociation degree and the stagnation point enthalpy, correcting the local specific heat ratio, and then according to a preset convergence condition, iterating to convergence to obtain the stagnation point enthalpy value.

Description

Technical Field

[0001] This invention relates to the field of aerodynamic thermal testing technology for aircraft, and in particular to a method and apparatus for measuring stagnation enthalpy in a subsonic flow field test in a high enthalpy wind tunnel. Background Technology

[0002] High-frequency induction plasma wind tunnels are one of the main types of equipment used for aerodynamic and thermal testing of aircraft. These wind tunnels can operate in both supersonic and subsonic modes. Under subsonic flow field conditions in the high-frequency induction wind tunnel, high-temperature gas flow generated from the plasma generator directly enters the test section and interacts with the test model. Due to the lack of acceleration from the Laval nozzle, the static temperature of the gas flow in the test section remains very high (>5000K), and the gas exhibits strong dissociation and ionization reactions. Determining the enthalpy of the subsonic flow field under these conditions presents new challenges: the fluid gas energy includes the sensible enthalpy represented by the energy levels of the gas (translational, rotational, and vibrational) and the chemical enthalpy carried by the atoms (N, O) after the gas dissociation reaction. When these atoms recombine at the model surface, they release heat and generate a huge catalytic heat flux. Therefore, it is necessary to improve existing enthalpy measurement methods to achieve a complete characterization of both sensible and chemical enthalpies.

[0003] The method of inversely estimating enthalpy based on stagnation point heat flux-pressure under supersonic flow conditions cannot be directly applied to subsonic flow fields. Under subsonic conditions, there is no bow shock wave in front of the model, and the local velocity gradient at the stagnation point needs to be corrected. Directly applying the stagnation point heat flux-pressure inverse formula will result in an overestimation of the stagnation point enthalpy.

[0004] Therefore, there is an urgent need to provide a method for measuring enthalpy under subsonic conditions. Summary of the Invention

[0005] To overcome the problems existing in the related technologies, this disclosure provides a method, apparatus, equipment and medium for measuring stagnation enthalpy in a high enthalpy wind tunnel subsonic flow field test, so as to solve the technical problems in the related technologies.

[0006] This specification provides one or more embodiments of a method for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel, including the following steps: In the subsonic flow field test in the high enthalpy wind tunnel, a subsonic high enthalpy flow field matching the atmospheric composition of a gas giant planet was generated by a high-frequency inductive plasma generator. The stagnation pressure and the static pressure of the flow field were collected by a measuring probe. Based on the ratio of the stagnation pressure to the static pressure of the flow field, combined with the local specific heat ratio, the local Mach number of the flow field was calculated, and the correction factor was determined based on the local Mach number and the local specific heat ratio. The first stagnation heat flux and the second stagnation heat flux at the same flow field location are obtained by a dual heat flux probe, wherein the dual heat flux probe is a probe with a first catalytic recombination coefficient and a second catalytic recombination coefficient on its surface, respectively. Using stagnation enthalpy and degree of dissociation as variables to be solved, a system of residual equations is constructed by combining the first stagnation heat flux, the second stagnation heat flux, and the correction factor. Based on the preset initial values ​​of the variables to be solved, and using the Newton-Raphson numerical iterative algorithm based on the residual equations, the correction amount of the variables to be solved is determined by calculating the partial derivative matrix and solving the linear equations. The variables to be solved are gradually corrected, and the local specific heat ratio is corrected according to the degree of dissociation and enthalpy of the current step. Then, the algorithm is iterated until convergence according to the preset convergence condition to obtain the enthalpy value of the enthalpy of the enthalpy.

[0007] This specification provides one or more embodiments of a device for measuring the stagnation enthalpy in a high-enthalpy wind tunnel subsonic flow field test, comprising: The parameter acquisition module is used in subsonic flow field tests in high-enthalpy wind tunnels to generate a subsonic high-enthalpy flow field that matches the atmospheric composition of a gas giant planet through a high-frequency inductive plasma generator. The module collects stagnation pressure and flow field static pressure through a measurement probe. Based on the ratio of stagnation pressure to flow field static pressure and the local specific heat ratio, the module calculates the local Mach number of the flow field and determines the correction factor based on the local Mach number and the local specific heat ratio. The stagnation heat flux acquisition module is used to measure the first stagnation heat flux and the second stagnation heat flux at the same flow field location through dual heat flux probes with a first catalytic recombination coefficient and a second catalytic recombination coefficient on their surfaces, respectively. The equation system construction module is used to construct a residual equation system by taking the enthalpy at stagnation and the degree of dissociation as the variables to be solved, and combining the first stagnation heat flux, the second stagnation heat flux, and the correction factor. The solution module is used to determine the correction amount of the variable to be solved based on the preset initial values ​​of the variable to be solved, the residual equation system, and the Newton-Raphson numerical iterative algorithm. It calculates the partial derivative matrix and solves the linear equation to determine the correction amount of the variable to be solved, and gradually corrects the variable to be solved. Based on the degree of dissociation and enthalpy of the current step, it corrects the local specific heat ratio γ, and then iterates until convergence according to the preset convergence condition to obtain the enthalpy value of the enthalpy of the enthalpy.

[0008] This specification provides one or more embodiments of a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the stagnation enthalpy measurement method for subsonic flow field tests in a high enthalpy wind tunnel as described above.

[0009] The present disclosure provides a method, apparatus, equipment, and medium for measuring stagnation enthalpy in a high-enthalpy wind tunnel subsonic flow field test. Its advantages are that, by using conventional methods such as heat flow and pressure measurement, and based on dual-catalytic heat flow measurement and local Mach number measurement and correction, it achieves accurate measurement of the enthalpy value of the subsonic flow field in a high-frequency induced plasma wind tunnel, filling the gap in enthalpy value measurement in subsonic (Ma < 1) high-enthalpy flow fields; and by decoupling the catalytic effect and Mach number correction, it achieves higher precision enthalpy value quantification. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A flowchart illustrating a method for measuring stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel, provided for one or more embodiments of this specification; Figure 2 A block diagram of a stagnation point enthalpy measuring device for a high enthalpy wind tunnel subsonic flow field test provided for one or more embodiments of this specification; Figure 3 This is a schematic diagram of the structure of a computer device provided for one or more embodiments of this specification. Detailed Implementation

[0012] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this invention.

[0013] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0014] Method Implementation Examples According to an embodiment of the present invention, a method for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel is provided, such as... Figure 1 The diagram shown is a flowchart of the stagnation enthalpy measurement method for a subsonic flow field test in a high-enthalpy wind tunnel provided in this embodiment. The stagnation enthalpy measurement method for a subsonic flow field test in a high-enthalpy wind tunnel according to this embodiment includes the following steps: Step S1: Based on the subsonic flow field test in the high-enthalpy wind tunnel, a subsonic high-enthalpy flow field matching the atmospheric composition of a gas giant planet is generated by a high-frequency inductive plasma generator. The stagnation pressure P0 and the static pressure P of the flow field are collected by a measuring probe. static Based on the ratio of stagnation pressure to static pressure in the flow field, and combined with the local specific heat ratio γ, the local Mach number Ma of the flow field is calculated, and the correction factor is determined based on the local Mach number and the local specific heat ratio γ.

[0015] In this embodiment, the subsonic high-enthalpy flow field generation process adapted to the simulation of a gas giant planet includes the following steps: Step 11, Plasma generator gas source configuration: Adjust the gas source according to the requirements of gas giant planet atmosphere simulation. H 2 He, CH A 4-unit mixed gas ratio is connected to the inlet of a high-frequency induction plasma generator. Step 12, Generator parameter control: Adjust the high-frequency induction power and gas flow rate to form a subsonic high-enthalpy flow field at the generator outlet, and maintain the static temperature of the flow field above 5000K to match the high temperature and high enthalpy environment of the atmosphere of the gas giant planet. Step 13, Flow field stabilization: Continuously monitor the pressure and temperature stability of the flow field at the generator outlet. Once the flow field parameter fluctuation is <±2%, proceed to the subsequent measurement steps.

[0016] In this embodiment, the measuring probe includes a dual heat flow probe and a pressure measuring probe. The dual heat flow probes are a first heat flow probe with a fully catalytically coated surface and a second heat flow probe with a fully non-catalytically coated surface. For example, the first heat flow probe has a silver film coated surface and a first catalytic recombination coefficient γ1, and the second heat flow probe has a silver film coated surface and a first non-catalytically coated surface. SiO A second heat flow probe with a Teflon coating and a second catalytic recombination coefficient γ2; both heat flow probes adopt a spherical head model and are arranged with coaxial calorimeters; the first heat flow probe has high catalytic characteristics and is adapted to the rapid recombination of gas atoms on the surface, while the second heat flow probe has low catalytic characteristics and inhibits the recombination of gas atoms on the surface.

[0017] The pressure probe is a cylindrical probe with a diameter of 10-15 mm and a pressure measuring hole diameter of 0.5-1 mm. The dual heat flux probe and the pressure probe are equipped with a horizontal feeding mechanism and are driven by a servo to quickly feed into the designated measurement position in the subsonic high enthalpy flow field, ensuring spatial consistency between heat flux and pressure data. The feeding speed is 1 m / s-2 m / s.

[0018] In this embodiment, the stagnation pressure and static pressure detection ends of the probe are connected to a high-precision pressure sensor (accuracy ≤ 0.1%FS) to collect real-time pressure data. The average value of ≥ 10 sets of data is taken continuously to reduce measurement error.

[0019] In this embodiment, the local Mach number Ma is calculated based on the ratio of stagnation pressure to static pressure in the flow field, combined with the local specific heat ratio γ. The correction factor is then calculated and determined based on the local Mach number and the local specific heat ratio γ, as follows: Local Mach number of the flow field: ; Where P0 is the stagnation pressure, Pstatic is the static pressure of the flow field, and the local specific heat ratio γ can be obtained through thermodynamic equilibrium calculations; The correction factor is determined based on the local Mach number of the flow field. As shown in the following formula: .

[0020] In this embodiment, the correction factor It needs to be adapted for subsonic (Ma < 1) scenarios to avoid applying the correction logic of supersonic flow fields and ensure the accuracy of subsequent enthalpy calculations.

[0021] Step S2: Obtain the first stagnation point heat flux at the same flow field location collected by dual heat flux probes. Second stagnation point heat flow The dual heat flow probe is a probe whose surface has a first catalytic recombination coefficient and a second catalytic recombination coefficient, respectively.

[0022] Step S3: Using stagnation enthalpy and degree of dissociation as variables to be solved, combined with the first stagnation heat flux... Second station heat flow The residual equation system is constructed by modifying the factors.

[0023] In this embodiment, the experimentally measured heat flux, correction factor, and the enthalpy and degree of dissociation to be determined are quantitatively correlated by defining a vector of variables to be solved and establishing a system of residual equations. The system of residual equations is as follows: ; ; in, H 0 represents the enthalpy at the stationary point. For the degree of dissociation, Stagnant heat flux is a quantitative calculation model for stagnant heat flux in a subsonic flow field in a high-enthalpy wind tunnel. Let R be a constant that includes the thermal properties of the gas, and R be the equivalent radius of the heat flux probe. H w is the wall enthalpy; Le is the Lewis number, with values ​​ranging from [1.2, 1.5], and a typical value of 1.3; h D The average dissociation energy is taken as 33.5 MJ / kg; For the degree of dissociation and catalytic complexation coefficient γ i Related catalytic factors.

[0024] In this embodiment, the residual equations are constructed using two measurements from the dual heat flux probes, transforming the coupled relationship between enthalpy, degree of dissociation, catalytic effect, and subsonic correction into a set of mathematical equations, thus realizing the two unknown quantities. H 0 and degree of dissociation The simultaneous decoupling.

[0025] In this embodiment, the stagnation heat flux of the subsonic high-enthalpy flow field is not equal to the simple gas convection heat flux, but rather the superposition of convective heat transfer (sensible enthalpy transfer) and chemical heat transfer (chemical enthalpy release) caused by the recombination of dissociated atoms on the probe surface. At the same time, the catalytic characteristics of the probe (which determine the atomic recombination efficiency) and the Lewis number (the coupling relationship between mass transfer and heat transfer) need to be considered for correction. Finally, the core term specially designed for the strong dissociation characteristics of the subsonic high-enthalpy flow field is used to solve the heat flux equation, reflecting the superposition effect of the chemical energy released by the recombination of dissociated atoms on the probe surface on the heat flux, thus realizing the full-factor quantification of heat flux.

[0026] F1 and F2 represent the measured heat flux and calculated heat flux based on the enthalpy-dissociation degree model, respectively, from the dual-catalytic heat flux probe. The deviation value between the calculated values ​​and the experimental measurements is required to be 0 by the residual equation system, that is, to achieve a complete match between the calculated values ​​of the model and the experimental measurements.

[0027] Step S4: Based on the preset initial values ​​of the variables to be solved, and using the Newton-Raphson numerical iteration algorithm based on the residual equation system, the correction amount of the variables to be solved is determined by calculating the partial derivative matrix and solving the linear equation. The variables to be solved are gradually corrected, and the local specific heat ratio γ is corrected according to the degree of dissociation and enthalpy of the current step. Then, the iteration is performed until convergence according to the preset convergence condition to obtain the enthalpy value of the enthalpy of the enthalpy.

[0028] In this embodiment, the process of solving for the stationary enthalpy value using the Newton-Raphson numerical iteration algorithm in step S4 includes the following steps: Step 41, Set initial values ​​for the variables to be solved ,in, The initial value of the local specific heat ratio γ is taken as , Hw The value is determined based on the hot wall temperature of the stagnation probe.

[0029] Step 42: Linearize the nonlinear residual equation system using the first-order approximation of Taylor expansion, and calculate the partial derivative matrix J. (k) The calculation is as follows: .

[0030] Step 43, establish linear equations The variable correction amount is solved by matrix inversion. X (k) ,Right now X (k) = [ H 0, ] T k is the number of iterations.

[0031] Step 44, then determine based on the set convergence threshold ε. If the value is less than ε, stop the iteration and output the stationary point enthalpy. H 0 and degree of dissociation Otherwise update X (k+1) =X (k) + X Feedback step 43 is performed and iteration continues; in this embodiment, ε is preferably 0.01.

[0032] Step 45: Output the stationary point enthalpy value based on step 44. H 0 and degree of dissociation Correct the local specific heat ratio γ. And recalculate the local Mach number Ma and correction factor. This enables multi-parameter linkage correction.

[0033] The stagnation enthalpy measurement method for subsonic flow field tests in a high-enthalpy wind tunnel provided in this embodiment has the following beneficial effects: (1) The method provided in this embodiment uses conventional means such as heat flow and pressure measurement, based on dual-catalytic heat flow measurement-local Mach number measurement and correction, to achieve accurate measurement of the enthalpy value of the subsonic flow field in the high-frequency induction plasma wind tunnel, filling the gap in the measurement of enthalpy value in the subsonic (Ma<1) high enthalpy flow field.

[0034] (2) The method provided in this embodiment achieves higher precision enthalpy quantification by decoupling the catalytic effect and Mach number correction.

[0035] Device Examples According to an embodiment of the present invention, a device for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel is provided, such as... Figure 2 The diagram shown is a block diagram of the stagnation enthalpy measuring device for a subsonic flow field test in a high-enthalpy wind tunnel provided in this embodiment. The stagnation enthalpy measuring device for a subsonic flow field test in a high-enthalpy wind tunnel according to this embodiment includes: Parameter acquisition module 10 is used in subsonic flow field experiments in high-enthalpy wind tunnels to generate a subsonic high-enthalpy flow field matching the atmospheric composition of a gas giant planet through a high-frequency inductive plasma generator, and to collect stagnation pressure P0 and static pressure P of the flow field through a measurement probe. static Based on the ratio of stagnation pressure to static pressure in the flow field, and combined with the local specific heat ratio γ, the local Mach number Ma of the flow field is calculated, and the correction factor is determined based on the local Mach number and the local specific heat ratio γ.

[0036] The stagnation heat flow acquisition module 20 is used to measure the first stagnation heat flow and the second stagnation heat flow at the same flow field location through dual heat flow probes with a first catalytic recombination coefficient and a second catalytic recombination coefficient on their surfaces, respectively.

[0037] The equation system construction module 30 is used to construct a residual equation system by taking the stagnation enthalpy and degree of dissociation as variables to be solved, and combining the first stagnation heat flux, the second stagnation heat flux, and the correction factor.

[0038] The solver module 40 is used to determine the correction amount of the variable to be solved based on the preset initial value of the variable to be solved, the residual equation system, and the Newton-Raphson numerical iteration algorithm. It calculates the partial derivative matrix and solves the linear equation to gradually correct the variable to be solved. Based on the degree of dissociation and enthalpy of the current step, it corrects the local specific heat ratio γ. Then, it iterates until convergence according to the preset convergence condition to obtain the enthalpy value of the enthalpy of the enthalpy.

[0039] In this embodiment, the measuring probe includes a dual heat flow probe and a pressure measuring probe. The dual heat flow probes are a first heat flow probe with a silver-plated surface and a first catalytic recombination coefficient γ1, and a second heat flow probe with a silver-plated surface. SiO A second heat flow probe with a Teflon coating and a second catalytic recombination coefficient γ2; both heat flow probes adopt a spherical head model and are arranged with coaxial calorimeters; the first heat flow probe has high catalytic characteristics and is adapted to the rapid recombination of gas atoms on the surface, while the second heat flow probe has low catalytic characteristics and inhibits the recombination of gas atoms on the surface.

[0040] The pressure probe is a cylindrical probe with a diameter of 10-15 mm and a pressure measuring hole diameter of 0.5-1 mm. The dual heat flux probe and the pressure probe are equipped with a horizontal feeding mechanism and are driven by a servo to quickly feed into the designated measurement position in the subsonic high enthalpy flow field, ensuring spatial consistency between heat flux and pressure data. The feeding speed is 1 m / s-2 m / s.

[0041] In this embodiment, the stagnation pressure and static pressure detection ends of the probe are connected to a high-precision pressure sensor (accuracy ≤ 0.1%FS) to collect real-time pressure data. The average value of ≥ 10 sets of data is taken continuously to reduce measurement error.

[0042] In this embodiment, the local Mach number Ma is calculated based on the ratio of stagnation pressure to static pressure in the flow field, combined with the local specific heat ratio γ. Then, the correction factor is calculated and determined based on the local Mach number and the local specific heat ratio γ, as follows: Local Mach number of the flow field: ; Where P0 is the stagnation pressure, P static For static pressure in the flow field; The correction factor is determined based on the local Mach number of the flow field. As shown in the following formula: .

[0043] In this embodiment, the correction factor It needs to be adapted for subsonic (Ma < 1) scenarios to avoid applying the correction logic of supersonic flow fields and ensure the accuracy of subsequent enthalpy calculations.

[0044] In this embodiment, the equation construction module 30 is used to quantitatively correlate the experimentally measured heat flux, correction factor, and the enthalpy and degree of dissociation to be determined by defining a vector of variables to be solved and establishing a residual equation system. The residual equation system is as follows: ; ; in, H 0 represents the enthalpy at the stationary point. For the degree of dissociation, Stagnant heat flux is a quantitative calculation model for stagnant heat flux in a subsonic flow field in a high-enthalpy wind tunnel. Let R be a constant that includes the thermal properties of the gas, and R be the equivalent radius of the heat flux probe. H w Let be the wall enthalpy; Le is the Lewis number, with values ​​[1.2, 1.5]. h D The average dissociation energy is taken as 33.5 MJ / kg; For the degree of dissociation and catalytic complexation coefficient γ i Related catalytic factors.

[0045] In this embodiment, the residual equations are constructed using two measurements from the dual heat flux probes, transforming the coupled relationship between enthalpy, degree of dissociation, catalytic effect, and subsonic correction into a set of mathematical equations, thus realizing the two unknown quantities. H 0 and degree of dissociation The simultaneous decoupling.

[0046] In this embodiment, the stagnation heat flux of the subsonic high-enthalpy flow field is not equal to the simple gas convection heat flux, but rather the superposition of convective heat transfer (sensible enthalpy transfer) and chemical heat transfer (chemical enthalpy release) caused by the recombination of dissociated atoms on the probe surface. At the same time, the catalytic characteristics of the probe (which determine the atomic recombination efficiency) and the Lewis number (the coupling relationship between mass transfer and heat transfer) need to be considered for correction. Finally, the core term specially designed for the strong dissociation characteristics of the subsonic high-enthalpy flow field is used to solve the heat flux equation, reflecting the superposition effect of the chemical energy released by the recombination of dissociated atoms on the probe surface on the heat flux, thus realizing the full-factor quantification of heat flux.

[0047] F1 and F2 represent the measured heat flux and calculated heat flux based on the enthalpy-dissociation degree model, respectively, from the dual-catalytic heat flux probe. The deviation value between the calculated values ​​and the experimental measurements is required to be 0 by the residual equation system, that is, to achieve a complete match between the calculated values ​​of the model and the experimental measurements.

[0048] In this embodiment, the solution module 40 uses the Newton-Raphson numerical iteration algorithm to determine the stationary point enthalpy, and includes the following sub-modules: The initial value setting submodule is used to set the initial values ​​of the variables to be solved. ,in, The initial value of the local specific heat ratio γ is taken as ; The derivative submodule is used to linearize the nonlinear residual equation system through a first-order approximation of Taylor expansion and to calculate the partial derivative matrix J. (k) The calculation is as follows: .

[0049] The correction calculation submodule is used to establish linear equations. The variable correction amount is solved by matrix inversion. X ,Right now X= [ H 0, ] T k is the number of iterations.

[0050] The comparison and judgment submodule is used to determine the convergence threshold ε based on the set threshold. If the value is less than ε, stop the iteration and output the stationary point enthalpy. H 0 and degree of dissociation Otherwise update X (k+1) =X (k) + X The feedback is sent to the correction calculation submodule; in this embodiment, ε is preferably 0.01.

[0051] The correction submodule is used to determine the stationary enthalpy value output by the submodule based on comparison. H 0 and degree of dissociation Correct the local specific heat ratio γ. And recalculate the local Mach number Ma and correction factor. This enables multi-parameter linkage correction.

[0052] The embodiments of the present invention are device embodiments corresponding to the above method embodiments. The specific operations of each module processing step can be understood with reference to the description of the method embodiments, and will not be repeated here.

[0053] like Figure 3As shown, the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the stagnation enthalpy measurement method for the high enthalpy wind tunnel subsonic flow field test described in the above embodiments.

[0054] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the stagnation point enthalpy measurement method of the high enthalpy wind tunnel subsonic flow field test described in the above embodiments.

[0055] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0056] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and the contents not described in detail in the specification of the present invention are well known to those skilled in the art.

Claims

1. A method for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel, characterized in that, Including the following steps: In the subsonic flow field test in the high enthalpy wind tunnel, a subsonic high enthalpy flow field matching the atmospheric composition of a gas giant planet was generated by a high-frequency inductive plasma generator, and the stagnation pressure and static pressure of the flow field were collected by a measuring probe. Based on the ratio of stagnation pressure to static pressure in the flow field, and combined with the local specific heat ratio, the local Mach number of the flow field is calculated, and the correction factor is determined based on the local Mach number and the local specific heat ratio. The first stagnation heat flux and the second stagnation heat flux at the same flow field location are obtained by a dual heat flux probe, wherein the dual heat flux probe is a probe with a first catalytic recombination coefficient and a second catalytic recombination coefficient on its surface, respectively. Using stagnation enthalpy and degree of dissociation as variables to be solved, a system of residual equations is constructed by combining the first stagnation heat flux, the second stagnation heat flux, and the correction factor. Based on the preset initial values ​​of the variables to be solved, and using the Newton-Raphson numerical iterative algorithm based on the residual equations, the correction amount of the variables to be solved is determined by calculating the partial derivative matrix and solving the linear equations. The variables to be solved are gradually corrected, and the local specific heat ratio is corrected according to the degree of dissociation and enthalpy of the current step. Then, the algorithm is iterated until convergence according to the preset convergence condition to obtain the enthalpy value of the enthalpy of the enthalpy.

2. The method for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel as described in claim 1, characterized in that, Also includes: The process of generating a subsonic high-enthalpy flow field adapted to simulations of gas giant planets includes the following steps: Plasma generator gas source configuration: According to the requirements of atmospheric simulation of gas giant planet, adjust the ratio of mixed gas and connect it to the gas inlet of high frequency induction plasma generator; Generator parameter control: Adjust the high-frequency induction power and gas flow rate to form a subsonic high-enthalpy flow field at the generator outlet, and maintain the static temperature of the flow field at a preset dimension to match the high temperature and high enthalpy environment of the atmosphere of a gas giant planet. Flow field stabilization: Continuously monitor the pressure and temperature stability of the flow field at the generator outlet. Once the flow field parameter fluctuation is less than ±2%, proceed with the measurement steps.

3. The method for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel as described in claim 1, characterized in that, The measuring probe includes a dual heat flow probe and a pressure probe. The dual heat flow probes are a first heat flow probe with a fully catalytic coating on its surface and a second heat flow probe with a fully non-catalytic coating on its surface. Both heat flow probes adopt a ball head model and are equipped with coaxial calorimeters.

4. The method for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel as described in claim 1, characterized in that, The local Mach number of the flow field is calculated based on the ratio of stagnation pressure to static pressure of the flow field, combined with the local specific heat ratio. The correction factor is then determined based on the local Mach number and the local specific heat ratio, as shown in the following formula: Local Mach number of the flow field: ; Where P0 is the stagnation pressure, P static The static pressure of the flow field is γ, and the local specific heat ratio is γ. The correction factor is determined based on the local Mach number of the flow field. As shown in the following formula: 。 5. The method for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel as described in claim 4, characterized in that, The residual equations are as follows: ； ； in, H 0 represents the enthalpy at the stationary point. For the degree of dissociation, This refers to the stagnation heat flux, a quantitative calculation model for stagnation heat flux in a subsonic flow field in a high-enthalpy wind tunnel. Let R be a constant that includes the thermal properties of the gas, and R be the equivalent radius of the heat flux probe. H w Le is the wall enthalpy; Le is the Lewis number; h D The average dissociation energy; For the degree of dissociation and catalytic complexation coefficient γ i The relevant catalytic factors include the first catalytic complexation coefficient γ1 and the second catalytic complexation coefficient γ2.

6. The method for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel as described in claim 5, characterized in that, The process of solving for the stationary point enthalpy using the Newton-Raphson numerical iterative algorithm includes the following steps: 1) Set the initial values ​​of the variables to be solved. ,in, The initial value of the local specific heat ratio γ is taken as ; 2) Linearize the nonlinear residual equation system using the first-order approximation of Taylor expansion, and calculate the partial derivative matrix J. (k) ; 3) Establish linear equations The variable correction amount is solved by matrix inversion. X (k) ,Right now X (k) = [ H 0, ] T k is the number of iterations; 4) Then, based on the set convergence threshold ε, determine... If the value is less than ε, stop the iteration and output the stationary point enthalpy. H 0 and degree of dissociation Otherwise update X (k+1) =X (k) + X Feedback step 3) and continue iterating; 5) Output the stationary point enthalpy value according to step 4). H 0 and degree of dissociation Correct the local specific heat ratio γ. And recalculate the local Mach number Ma and correction factor. .

7. A device for measuring the stagnation enthalpy in a subsonic flow field test in a high-enthalpy wind tunnel, characterized in that, include: The parameter acquisition module is used to generate a subsonic high-enthalpy flow field matching the atmospheric composition of a gas giant planet through a high-frequency induction plasma generator in a high-enthalpy wind tunnel subsonic flow field test, and to collect stagnation pressure and flow field static pressure through a measurement probe. Based on the ratio of stagnation pressure to static pressure in the flow field, and combined with the local specific heat ratio, the local Mach number of the flow field is calculated, and the correction factor is determined based on the local Mach number and the local specific heat ratio. The stagnation heat flux acquisition module is used to measure the first stagnation heat flux and the second stagnation heat flux at the same flow field location through dual heat flux probes with a first catalytic recombination coefficient and a second catalytic recombination coefficient on their surfaces, respectively. The equation system construction module is used to construct a residual equation system by taking the enthalpy at stagnation and the degree of dissociation as the variables to be solved, and combining the first stagnation heat flux, the second stagnation heat flux, and the correction factor. The solution module is used to determine the correction amount of the variable to be solved based on the preset initial values ​​of the variable to be solved, the residual equation system, and the Newton-Raphson numerical iterative algorithm. It calculates the partial derivative matrix and solves the linear equation to determine the correction amount of the variable to be solved, and gradually corrects the variable to be solved. Based on the degree of dissociation and enthalpy of the current step, it corrects the local specific heat ratio γ, and then iterates until convergence according to the preset convergence condition to obtain the enthalpy value of the enthalpy of the enthalpy.

8. The stagnation enthalpy measuring device for subsonic flow field tests in a high-enthalpy wind tunnel as described in claim 7, characterized in that, The local Mach number Ma is calculated based on the ratio of stagnation pressure to static pressure in the flow field, combined with the local specific heat ratio γ. Then, the correction factor is calculated and determined based on the local Mach number and the local specific heat ratio γ, as follows: Local Mach number of the flow field: ; Where P0 is the stagnation pressure, P static The static pressure of the flow field is γ, and the local specific heat ratio is γ. The correction factor is determined based on the local Mach number of the flow field. As shown in the following formula: 。 9. The stagnation enthalpy measuring device for subsonic flow field tests in a high-enthalpy wind tunnel as described in claim 8, characterized in that, The residual equations are as follows: ； ； in, H 0 represents the enthalpy at the stationary point. For the degree of dissociation, This refers to the stagnation heat flux, a quantitative calculation model for stagnation heat flux in a subsonic flow field in a high-enthalpy wind tunnel. Let R be a constant that includes the thermal properties of the gas, and R be the equivalent radius of the heat flux probe. H w Le is the wall enthalpy; Le is the Lewis number; h D The average dissociation energy; For the degree of dissociation and catalytic complexation coefficient γ i The relevant catalytic factors include the first catalytic complexation coefficient γ1 and the second catalytic complexation coefficient γ2.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the stagnation enthalpy measurement method for subsonic flow field tests in high enthalpy wind tunnels as described in any one of claims 1 to 6.

Images